<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
        <meta
            name="viewport"
            content="width=device-width, minimal-ui, viewport-fit=cover, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0, user-scalable=no"
        />
        <link rel="icon" type="image/png" href="assets/favicon.png" />

        <title>OGL • Wireframe</title>
        <link href="assets/main.css" rel="stylesheet" />
    </head>
    <body>
        <div class="Info">Wireframe. Model by Google Poly</div>
        <script type="module">
            import { Renderer, Camera, Transform, Texture, Program, Geometry, Mesh } from '../src/index.mjs';

            const vertex = /* glsl */ `
                attribute vec2 uv;
                attribute vec3 position;
                attribute vec3 normal;

                uniform mat4 modelViewMatrix;
                uniform mat4 projectionMatrix;
                uniform mat3 normalMatrix;

                varying vec2 vUv;
                varying vec3 vNormal;

                void main() {
                    vUv = uv;
                    vNormal = normalize(normalMatrix * normal);
                    
                    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
                }
            `;

            const fragment = /* glsl */ `
                precision highp float;

                uniform float uTime;
                uniform sampler2D tMap;

                varying vec2 vUv;
                varying vec3 vNormal;

                void main() {
                    vec3 normal = normalize(vNormal);
                    vec3 tex = texture2D(tMap, vUv).rgb;
                    
                    vec3 light = normalize(vec3(0.5, 1.0, -0.3));
                    float shading = dot(normal, light) * 0.15;
                    gl_FragColor.rgb = tex + shading;
                    gl_FragColor.a = 1.0;
                }
            `;

            {
                const renderer = new Renderer({ dpr: 2 });
                const gl = renderer.gl;
                document.body.appendChild(gl.canvas);
                gl.clearColor(1, 1, 1, 1);

                const camera = new Camera(gl, { fov: 35 });
                camera.position.set(5, 3, 6);
                camera.lookAt([0, 0, 0]);

                function resize() {
                    renderer.setSize(window.innerWidth, window.innerHeight);
                    camera.perspective({ aspect: gl.canvas.width / gl.canvas.height });
                }
                window.addEventListener('resize', resize, false);
                resize();

                const scene = new Transform();

                const texture = new Texture(gl);
                const img = new Image();
                img.onload = () => (texture.image = img);
                img.src = 'assets/croissant.jpg';

                const program = new Program(gl, {
                    vertex,
                    fragment,
                    uniforms: {
                        tMap: { value: texture },
                    },
                });

                let lineLoopMesh, wireframeMesh;
                loadModel();
                async function loadModel() {
                    const data = await (await fetch(`assets/croissant.json`)).json();

                    // Regular geometry with no modifications to be used with gl.LINE_LOOP version
                    const geometry = new Geometry(gl, {
                        position: { size: 3, data: new Float32Array(data.position) },
                        uv: { size: 2, data: new Float32Array(data.uv) },
                        normal: { size: 3, data: new Float32Array(data.normal) },
                    });

                    // Using gl.LINE_LOOP or gl.LINE_STRIP as the draw mode will give an approximate wireframe.
                    // This is a simpler, lighter option if accuracy is not important (i.e. debugging).
                    lineLoopMesh = new Mesh(gl, { mode: gl.LINE_LOOP, geometry, program });
                    lineLoopMesh.setParent(scene);
                    lineLoopMesh.position.y = 1;

                    // For an accurate wireframe, triangle vertices need to be duplicated to make line pairs.
                    // Here we do so by generating indices. If your geometry is already indexed, this needs to be adjusted.
                    let index = new Uint16Array((data.position.length / 3 / 3) * 6);
                    for (let i = 0; i < data.position.length / 3; i += 3) {
                        // For every triangle, make three line pairs (start, end)
                        index.set([i, i + 1, i + 1, i + 2, i + 2, i], i * 2);
                    }

                    const wireframeGeometry = new Geometry(gl, {
                        position: { size: 3, data: new Float32Array(data.position) },
                        uv: { size: 2, data: new Float32Array(data.uv) },
                        normal: { size: 3, data: new Float32Array(data.normal) },
                        index: { data: index },
                    });

                    // use the gl.LINES draw mode
                    wireframeMesh = new Mesh(gl, { mode: gl.LINES, geometry: wireframeGeometry, program });
                    wireframeMesh.setParent(scene);
                    wireframeMesh.position.y = -1;
                }

                requestAnimationFrame(update);
                function update() {
                    requestAnimationFrame(update);

                    if (lineLoopMesh) lineLoopMesh.rotation.y -= 0.005;
                    if (wireframeMesh) wireframeMesh.rotation.y += 0.005;

                    renderer.render({ scene, camera });
                }
            }
        </script>
    </body>
</html>
